After finishing Taya's quest line, more quests will be generated randomly, but a player won't recieve any more limited Hats. The rewards that Tanning Taya then gives to you are either Mythical Crates/Eggs or Rebirth Tokens.

Trivia

Tanning Taya is one of the first female NPCs and quest givers, the other one being Candy Cassy. Both were introduced in the Quest Givers update.